Used Rotella T (5-40) syn for first time yesterday ... initial impressions:

1. Reddish in color
2. Additives "smell" totally different than M1 (15-50); R-T has a very "industrial" odor (somewhat akin to rear differential lubricant)
3. Did not seem as "slimy" to the touch and did not seem to "drip" down the sides of the containers as rapidly as M1 does
4. On start up R-T took a bit longer than M1 to come up to pressure on gauge
5. With fully warmed engine (80C +/-), and at idle R-T appears to run about 0.25-0.5 bar higher than M1
6. On quick rev of engine, R-T seems a bit slower to max pressure than M1

Not sure what all the above means, but may net out that M1, at 5-40 is actually thicker in use than M1 15-50?

Reason for switch is that while R-T does not have the same attributes as M1, it is relatively close and does cost about 30%less.

Anyone else with same experience with R-T?

__________________
George Stephenson
1991 350 SDL (200K and she ain't bent, yet)
former 2002 E320 4Matic Wagon - good car
former 1985 300 CD - great car
former 1981 300 TD - good car
former 1972 280 SEL - not so good car
a couple of those diesel Rabbits ...40-45 mpg